[gimp] Issue #7837: gimp_installation_directory() in macOS doesn't know about…

[Jehan <jehanp src gnome org>]

commit bcdb1cdb6a99d533d677c529f466217ab3604111
Author: Jehan <jehan girinstud io>
Date:   Wed Feb 9 12:47:37 2022 +0100

    Issue #7837: gimp_installation_directory() in macOS doesn't know about…
    
    … extensions yet.

 libgimpbase/gimpenv.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/libgimpbase/gimpenv.c b/libgimpbase/gimpenv.c
index 6a2ef9a8a5..00e16bf7b9 100644
--- a/libgimpbase/gimpenv.c
+++ b/libgimpbase/gimpenv.c
@@ -424,9 +424,12 @@ gimp_installation_directory (void)
 
         toplevel = g_strdup (basepath);
       }
-    else if (! strcmp (dirname, "plug-ins"))
+    else if (! strcmp (dirname, "plug-ins") ||
+             ! strcmp (dirname, "extensions"))
       {
-        /*  same for plug-ins in subdirectory, go three levels up from prefix/lib/gimp/x.y  */
+        /*  same for plug-ins and extensions in subdirectory, go three
+         *  levels up from prefix/lib/gimp/x.y
+         */
 
         gchar *tmp  = g_path_get_dirname (basepath);
         gchar *tmp2 = g_path_get_dirname (tmp);